Reticulocytes are newly developed, young red blood cells (RBCs). RBCs are produced in bone marrow and released into the blood on a regular basis to replace RBCs that have aged, degraded or been lost due to bleeding. Most reticulocytes develop into mature RBCs within a day of being released into the blood. Reticulocytes typically account for 0.5 to 2 percent of RBCs in circulation. The percentage determined in the Reticulocyte Count Blood Test is an indicator of recent bone marrow activity.
Many conditions can affect the percentage of reticulocytes present. For example, in patients with acute or chronic bleeding or anemia, the production rate of new RBCs may increase to make up for the loss/early destruction of such cells, and RBCs may be released into the blood sooner than normal, resulting in a higher percentage of reticulocytes in circulation. A high reticulocyte count accompanied by a high RBC count can indicate overproduction of RBCs, which can result from smoking cigarettes or conditions such as polycythemia vera and excess erythropoietin (a hormone critical for the production of RBCs). Patients with a bone marrow disorder or other conditions that affect the bone marrow’s function may not produce enough new RBCs, thus, the percentage of reticulocytes present will be low. Decreased RBC production can also result from chemotherapy or radiation treatment and deficiencies of erythropoietin and nutrients such as iron, vitamin B12 and folate.
The Reticulocyte Count Blood Test will not diagnose the cause of abnormal reticulocyte levels. It should be used as an indicator that additional testing is necessary and to monitor the return of normal bone marrow function following bone marrow transplant and treatment for conditions causing decreased RBC production.
The Reticulocyte Count Blood Test is also known as Retic Count and Reticulocyte Percent. Fasting is not required prior to this test, and results will be available within one to two days. This low-cost test does not require insurance or a doctor’s order to purchase.